Semiconductor element and manufacturing method thereof

The invention relates to a semiconductor element and a manufacturing method thereof. The method for manufacturing the semiconductor element comprises the following steps of: forming a fin structure with a stack of alternating first semiconductor layers and second semiconductor layers on a substrate; forming a dummy gate structure across the fin structure; etching the plurality of portions of the fin structure to expose the plurality of portions of the substrate; forming a source/drain stress source on the exposed portions of the substrate; removing the dummy gate structure after forming the source/drain stressor; after removing the dummy gate structure, removing the first semiconductor layer so that the second semiconductor layer is suspended between the source/drain stressors; and forming a gate structure to surround each of the suspended second semiconductor layers. Each source/drain stressor includes a first source/drain layer and a second source/drain layer over the first source/drain layer. An atomic con